SummaryOne–hundred and ninety–five patients with toenail tinea unguium were recruited to a multicentre double–blind clinical trial. Patients were given 250mg terbinafine or 200 mg itraconazole daily for 12 weeks, with follow–up for a further 40 weeks. At the end of the study, mycological cure rates were 81% (70/86 assessed) for terbinafine and 63% (53/84 assessed) for itraconazole (two–tailed, P<0·05). The length of unaffected nail was 9·44 mm in the terbinafine group and 7·85 mm in the itraconazole group (two–tailed, P<0·05). Patient self–assessment also favoured terbinafine, with 65% evaluating it as good to very good, compared with 58% for itraconazole. Before treatment the terbinafine group had a mean of 6·7 and the itraconazole group 6·3 affected nails per patient. Total cure was achieved in 69% of terbinafine and 61% of itraconazole affected nails. We conclude that terbinafine is more effective than itraconazole In the treatment of toen